Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2002
Sammendrag
Salatbladskimmel (Bremia lactucae) har forårsaket store problemer i frilandssalat på Østlandet de siste årene. I et forprosjekt i 2001 ble det sett på smittekilder, raser og strategier for bekjempelse med minst mulig bruk av plantevernmidler. Mulige smittekilder er omtalt. Videre er det gitt resultater fra rasetestingen i 2001, og fra feltforsøk med to varslingsmodeller og ulike fungicider.
Sammendrag
Artikkelen gir en oversikt over tørråtesoppen og dens skadevirkning. Symptomer, soppens biologi og strategier for bekjempelse er beskrevet.
Sammendrag
A quantitative multiplex real-time PCR procedure was developed to monitor the dynamics in Norway spruce (Heterobasidion annosum) pathosystem. The assay reliably detected down to 1 pg of H. annosum DNA and 1 ng of host DNA in multiplex conditions. As a comparative method for quantifying fungal colonization,we applied the ergosterol assay. There was a very high correlation between the results obtained with the two methods, this strengthening the credibility of both assays. The advantages and disadvantages of these assays are discussed.
Sammendrag
Determining the level of pathogenic fungi and other microorganisms during colonization of the host is central in phytopathological studies. A direct way to monitor fungal hyphae within the host is microscopic examination, but chitin and ergosterol-levels are commonly used to indirectly measure the amount of fungus present. Recently real-time PCR technology is being used to follow infection agents in host tissues. We study the molecular basis of host defense responses, using the coniferous host Norway spruce infected with the pathogen Heterobasidion parviporum as the experimental system. This basidiomycete and the closely related pathogen H. annosum are the major root rot causing pathogens in conifers. To screen host material for differential resistance towards H. parviporum, it is a necessity to quantify the fungal colonization of the host tissues. Therefore, we aimed to develop and compare the sensitivity of a real-time PCR to an ergosterol based method for determining the rate of colonization, and applied the methods to rank the infection level of the pathogen on the spruce clones 053 and 589. We developed a quantitative multiplex real-time PCR procedure that reliably detecting down to 1pg H. parviporum DNA and 1ng host DNA. There was a very high correlation between the fungal-biomass/total-biomass and fungal-DNA/total-DNA rankings obtained with ergosterol and real-time PCR, strengthening the credibility of both methods. Based on both ergosterol and real-time PCR, it was clear that the clone 053 was hosting more fungal biomass than clone 589. The results indicate that this real-time procedure can be a useful method to screen different spruce material for their relative resistance to the pathogen H. parviporum.
Sammendrag
One of our main interests is to learn about the molecular basis of host defense responses, using the coniferous host Norway spruce infected with the pathogen Heterobasidion parviporum as the experimental system. This basidiomycete and the closely related pathogen H. annosum are the major root rot causing pathogens in conifers.To screen host material for differential resistance towards H. parviporum, it is a necessity to quantify the fungal colonization of the host tissues. Therefore, we aimed to develop and compare the sensitivity of a real-time PCR to an ergosterol based method for determining the rate of colonization. We developed a quantitative multiplex real-time PCR procedure that reliably detecting down to 1pg H. parviporum DNA and 1ng host DNA.There was a very high correlation between the fungal-biomass/total-biomass and fungal-DNA/total-DNA rankings obtained with ergosterol and real-time PCR, strengthening the credibility of both methods. The results indicate that this real-time procedure can be a useful method to screen different spruce material for their relative resistance to the pathogen H. parviporum.
Sammendrag
Magnesiummangel fører til store skadar på forskjellege bartreartar som vert bruka til klyppegrønt. I nokre felt med lawsonsypress (Chamaecyparis lawsoniana) er skadane så omfattande at baret ikkje er salsvare. I beste fall krev det mykje ekstra arbeid å fjerna skadde parti. Våren 2001 vart det også meldt om mangelsymptom på nordmannsedelgran (Abies nordmanniana) i juletrefelt. I artikkelen vert det vist symptom og diskutert kvifor det kan oppstå mangel og kva tiltak som er aktuelle.
Sammendrag
Nålefall er eit stort problem i nokre juletrefelt. Både nyplanta og hausteferdige tre kan verta skadde. Det er fleire årsakar til nålefall, mellom anna insekt, midd, Mg-mangel og soppangrep. Rustsoppar, gråskimmel, Phomopsis sp. og andre soppar som drep nåler, fører til at dei daude nålene fell av, men soppen Rhizosphaera sp. er spesielt kjent for å føra til nålefall.
Sammendrag
Alle som driv med juletre, har erfart at det å produsera eit juletre av god kvalitet ikkje er eit arbeide som gjer seg sjølv. I 8-10 år må felta gjødslast og haldast ugrasreine. Trea må toppskotregulerast og formskjerast. God plantekultur er likevel ingen garanti for å få fram trea. Hovudårsaka til utgang er ulike soppsjukdomar, men skadedyr (til dømes insekt, midd, mus, hare og rådyr) og ubalansert næringstilgong kan også øydeleggja trea. Dessutan spelar været inn. Trea kan få både salt-, vind- og frostskade, spesielt dersom ein ikkje plantar ein planteart eller proveniens som er tilpassa klima på veksestaden. Gjennom prosjektet "Kartlegging og bekjemping av skadegjerarar i klyppegrønt- og juletreproduksjonen" har vi funne årsaka til ein del av dei sjukdomsproblema juletrenæringa slit med. I denne artikkelen vert tre aktuelle skadebilete omtala - skadde røter (rotròte), småplanter som daudar på grunn av soppen Phomopsis og nålefall på større tre.
Sammendrag
Gråskimmel (Botrytis cinerea) kan gi skade på mange ulike planteartar. Alle juletreartane våre er utsette. Særleg kan angrepa vera omfattande i tette bestand med overvatning eller i nedbørsrike vekstsesongar.
Forfattere
Håvard EikemoSammendrag
To investigate the variability in Phytophthora cactorum, 44 isolates from different geographic locations were collected. The isolates originated from various plant species, but the majority were crown rot and leather rot isolates from strawberry. DNA was extracted from all isolates, and examined by AFLP using seven different primer combinations. The resulting dendrogram revealed that isolates from crown rot in strawberries from all locations showed a very low degree of variation, and were clearly separated from the more variable leather rot isolates (of strawberry fruits) and isolates from other hosts. The separation of isolates with and without the ability to cause crown rot was confirmed in a pathogenesis test on strawberry plants. Several methods of screening strawberry cultivars for resistance to Phytophthora cactorum were tested and evaluated in this study. The methods involved both fresh and cold stored plants, and either mycelium on agar or a zoospore suspension was used to inoculate wounded or unwounded plants. Also inoculation of detached leaves and inoculation of plants in vitro were tested as possible methods of screening for resistance. Several of these methods discriminated well between cultivars, but they varied in reproducibility and accuracy. The preferred method was inoculation of unwounded, cold stored plants with a zoospore suspension. It was the least laborious method, and the results were reproducible when the same cultivars were tested several times over several years. Sammendraget er redigert.